---
title: "Runoff Election — AP Comp Gov Definition & Exam Guide"
description: "A runoff election is a second round of voting held when no candidate wins a majority. Key for AP Comp Gov Topic 4.2 and Russia, Iran, and Nigeria's executives."
canonical: "https://fiveable.me/ap-comp-gov/key-terms/runoff-election"
type: "key-term"
subject: "AP Comparative Government"
unit: "Unit 4"
---

# Runoff Election — AP Comp Gov Definition & Exam Guide

## Definition

A runoff election is a second round of voting, usually between the top two candidates, held when no one wins an absolute majority (over 50%) in the first round. In AP Comp Gov, Russia and Iran use runoff systems for their presidential elections, ensuring the winner has majority support.

## What It Is

A runoff election is a second round of voting that kicks in when no candidate clears 50% of the vote in the first round. The top two finishers face off head-to-head, which guarantees that someone walks away with an actual majority. That's the whole point. [Plurality](/ap-comp-gov/key-terms/plurality "fv-autolink") systems let a candidate win with 35% while 65% of voters wanted someone else. Runoff systems don't allow that.

In [AP Comp Gov](/ap-comp-gov "fv-autolink"), runoffs show up in presidential [election rules](/ap-comp-gov/unit-4 "fv-autolink"). Russia and Iran both use two-round majority systems for their presidents. Nigeria has a twist on this idea, since a presidential candidate needs a plurality of the national vote *plus* at least 25% of the vote in two-thirds of the 36 states. Fail either test and you get a runoff. These rules connect directly to EK DEM-2.B.3, which says different presidential election systems have different rules for determining winners.

## Why It Matters

Runoff [elections](/ap-comp-gov/key-terms/elections "fv-autolink") live in **[Topic 4.2](/ap-comp-gov/unit-4/objectives-election-rules/study-guide/LQynGtBwiEOJTJsYvN3V "fv-autolink") (Objectives of Election Rules)** in **Unit 4: Party and Electoral Systems and Citizen Organizations**, supporting learning objective **AP Comp Gov 4.2.A**, which asks you to explain how election rules serve different regime objectives. A runoff requirement isn't a random procedural detail. It's a deliberate design choice that signals what a regime wants its winner to have, which is broad majority legitimacy rather than just the biggest slice of a fragmented vote. Nigeria's version adds a federalism goal on top, forcing presidential candidates to build support across ethnic and regional lines instead of winning on one region alone. When the exam asks why a country structures elections the way it does, runoff rules are one of your clearest examples of rules serving objectives.

## Connections

### [First-Past-the-Post (Unit 4)](/ap-comp-gov/key-terms/first-past-the-post)

FPTP is the runoff's opposite. Under FPTP, whoever gets the most votes wins immediately, even with 30%, so no second round ever happens. Mexico elects its president this way, with a single plurality round. Comparing Mexico's plurality rule to [Russia](/ap-comp-gov/key-terms/russia "fv-autolink")'s majority-runoff rule is a classic Topic 4.2 contrast.

### [Executive Branch (Unit 2)](/ap-comp-gov/key-terms/executive-branch)

Runoffs only matter for directly elected executives. Russia's and Iran's presidents face them, but the UK's [prime minister](/ap-comp-gov/key-terms/prime-minister "fv-autolink") never could, because the PM isn't elected by national popular vote at all. The PM emerges from the legislature. How an executive is selected is exactly what the 2023 comparative FRQ asked about.

### [Electoral competition (Unit 4)](/ap-comp-gov/key-terms/electoral-competition)

Runoff rules shape competition by letting voters back smaller-party candidates in round one without 'wasting' their vote, then consolidating around two finalists. In practice, though, [authoritarian regimes](/ap-comp-gov/key-terms/authoritarian-regimes "fv-autolink") like Russia and Iran often manage candidate access so tightly that the runoff threshold is rarely triggered.

### [Accountability (Unit 4)](/ap-comp-gov/key-terms/accountability)

Majority-runoff systems boost the winner's claim to legitimacy, since over half the voters chose them in the final round. That stronger mandate is one of the regime objectives 4.2.A wants you to connect to election rules.

## On the AP Exam

Runoff elections show up mostly in multiple-choice questions tied to Topic 4.2. Typical stems ask which outcome would trigger a second round in Russia's presidential system, what happens when a Nigerian candidate wins 40% nationally but misses the 25%-in-two-thirds-of-states threshold, or which course country requires a majority in a second round. You need to do three things: state the trigger (no first-round majority), name the countries that use runoffs (Russia and Iran, with Nigeria's hybrid threshold rule), and explain the objective the rule serves (majority legitimacy, or in Nigeria's case, cross-regional support). On FRQs, the 2023 Comparative Analysis question asked you to compare executive selection processes across two course countries, and a runoff rule is exactly the kind of specific institutional detail that earns points in that comparison.

## runoff election vs First-Past-the-Post (plurality)

Both are rules for deciding who wins, but they set different bars. First-Past-the-Post awards victory to whoever has the most votes, full stop, even if that's well under 50%. A runoff system requires an absolute majority, so a first-round result like 45%-30%-25% forces a second round between the top two. Quick country check for the exam: Mexico's president wins by plurality (one round, no runoff), while Russia's and Iran's presidents must win a majority, with a runoff if nobody does.

## Key Takeaways

- A runoff election is a second round of voting between the top two candidates, triggered when no one wins an absolute majority in the first round.
- Russia and Iran both use two-round majority runoff systems to elect their presidents.
- Nigeria's president must win a plurality nationally and at least 25% of the vote in two-thirds of the 36 states, or the election goes to a runoff. This rule forces candidates to build cross-regional coalitions.
- Runoff rules serve a regime objective, which is making sure the winner has majority legitimacy rather than just the largest minority of votes (LO AP Comp Gov 4.2.A).
- Mexico is the contrast case. Its president wins by simple plurality in a single round, so no runoff is possible there.
- Runoffs apply to directly elected executives, so they're irrelevant for the UK, where the prime minister comes out of Parliament instead of a national vote.

## FAQs

### What is a runoff election in AP Comp Gov?

It's a second round of voting held when no candidate wins more than 50% in the first round, usually between the top two finishers. In the AP course, Russia and Iran use runoff systems for presidential elections.

### Which AP Comp Gov countries use runoff elections?

Russia and Iran use two-round majority runoffs for their presidents. Nigeria uses a hybrid, where a candidate needs a national plurality plus 25% of the vote in two-thirds of its 36 states, with a runoff if those thresholds aren't met.

### Does Mexico have runoff elections for president?

No. Mexico elects its president by simple plurality in a single round, so a candidate can win with less than 50% of the vote and no second round occurs. That makes Mexico the go-to contrast with Russia and Iran on the exam.

### How is a runoff election different from first-past-the-post?

First-past-the-post awards the win to whoever gets the most votes, even without a majority. A runoff system demands an absolute majority and adds a second round between the top two candidates if nobody reaches it in round one.

### Why do countries use runoff elections?

To guarantee the winner has majority support, which strengthens the executive's legitimacy. Nigeria's version adds another goal, forcing presidential candidates to win support across many states so they can't rely on a single region or ethnic group.

## Related Study Guides

- [4.2 Objectives of Election Rules ](/ap-comp-gov/unit-4/objectives-election-rules/study-guide/LQynGtBwiEOJTJsYvN3V)

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